When, during the blowing period of a steel refining process, oxygen is introduced into a steelmaking converter, of either the top- or bottom-blown type, large quantities of gaseous effluent are generated by the chemical reaction between the oxygen and the high temperature molten metal in the converter. The effluent is discharged from the mouth of the converter into a gas collecting hood which conducts the same to gas cleaning apparatus for appropriate processing prior to its being discharged to the atmosphere. Gas-collecting hoods of the type involved are customarily provided with a sliding skirt that is telescopically mounted on the end of the hood adjacent the converter mouth and vertically movable with respect to the hood end from a lower position in which the skirt abuts the converter to seal the junction between the converter and the hood and a raised position whereby air for combustion from the effluent gas can be admitted to the hood interior.
Part of the gas containment structure of a converter installation of the described type includes a vessel enclosure through the upper wall of which the hood must extend in order to establish gas communication between the converter and the hood interior. In the past, the opening provided in the enclosure for penetration of the hood had to provide sufficient clearance in order to accommodate the movable skirt and the mechanism for operating the same. Although this clearance space was maintained as small as possible, it nonetheless provided ample opportunity for egress of the effluent gases from the converter especially during periods of high reaction activity thus permitting unacceptably large amounts of gas to leak from the system into the surrounding atmosphere.
It is to the improvement of such gas containment apparatus therefore that the present invention is directed.